Yes - KSSquared - the Feather Duster CAN touch the stara polyps - they should not "kill" each other - BUT, they might "irritate" each other. Meaning that either the star polyps might not come out for a while, or the Feather Duster worm might not come out (IF the opening of the tube it lives in, is as low as the star polyps)....

You should be able to prop the feather duster between rocks, or perhaps even in the sand (if you have a substrate).....